Mongo database

MongoDB brief introduction

1） Open source database system based on distributed file storage .

2） For the purpose of WEB Applications provide scalable, high-performance data storage solutions

3) Store data as a document , Document similar to Json Format ,

{
    name:" Xiao Ming ",
    age:16,
    address: {city:" Changsha ", country:"china"}
}

5、 ... and 、 data type

1） type

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2）MongoDB Entry and exit

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 Get into   mongo    sign out   exit

6、 ... and 、 The document operation

1） Add the document （ data ）

db. Collection name .insert(document Every piece of data , It's just one. document, It's just one. json

 db.student.insert({name:'xiaoming', age:18})
 When adding a document , If you don't specify _id Parameters 
MongoDB The document is assigned a unique ObjectId
 example ： db.student.insert({'_id':1, name:'xiaoming', age:18})
 Add multiple documents 
db.student.insert([
    {name:xiaoming', sex:' male ', age:16},
    {name:’xiaobai', sex:' male ', age:18},
    {name:’moran‘, sex:’ Woman ', age:18},
])

2） Query the document （ data

db. Collection name .find([conditions]) MongoDB The conditional statements of are also very powerful , The following content may cause discomfort , Please prepare yourself for

1. View all data in the collection ： db.student.find()
2. Format display ： db.student.find().pretty()
3. View the data that meets the conditions ： db.student.find({name:'xiaoming'})

3） Nightmare conditions

The operator	describe
$ne	It's not equal to
$gt	Greater than
$lt	Less than
$gte	Greater than or equal to
$lte	Less than or equal to

Example ：db.user.find({‘age’: {’$ne’: 45}})

1.and Conditions

{$and:[{expression1}, {expression1}, ...]   }

2.or Conditions

{$or:[{expression1}, {expression1}, ...]   }

3.and and or A mixture of

db.table.find({$or:[{$and:[{sex:' Woman '}, {age:18}]},{$and:[{sex:' male '}, {age:{$gt:18}}]}]})

4） Modify the document （ data ）

1.db. Collection name

.update(<query>, <update>, {multi:<boolean>}

2. Modify a piece of data

db.table.update({sex:' male '}, {age:20})

3. Specify property modification

 { $set: {age:20} }
 db.table.update({name:'xiaoming'}, {$set: {age:666, sex: 'xx'}} )

4. Update all documents in the collection that meet the conditions

{ multi: true } 
db.table.update({sex:' male '}, {$set:{sex:' Woman '}}, { multi:true} )

5） Delete the document （ data ）

1.db. Collection name

.remove(<query>,  {justOne:<boolean>})

2. Delete all documents in the collection

db.table.remove({})

3. Delete all documents that meet the conditions in the collection

db.table.remove({sex: ' male '})

4. Delete only the first document in the set that meets the conditions

{ justOne: true } 
db.table.remove({sex:' male '}, { justOne:true} )

7、 ... and 、Python And MogoDB Interaction

1） install

pip install pymongo

2） Establishing a connection

client = pymongo.MongoClient()

3） Specify database

db = client[ Database name ]

4） Specify the collection

collection=db[ Collection name ]

5） Basic use

1. Search for documents

find()

2. Add the document

insert()

3. Modify the document

update()

4. Delete the document

remove()

6） The main points of

1. lookup

 Find a document ： find_one()
 Find all ：find()

2. add to

 Add a document ：insert_one
 Add more than one ：insert_many()

3. Delete

 Delete a document ：delete_one
 Delete multiple ：delete_many()

4. modify

 Modify a document ： update_one
 Modify multiple ：update_many()

6） take Mongodb Decoration into class

import pymongo


# 1. Establishing a connection 
client = pymongo.MongoClient()
# 2. Specify database 
db = client["py_49"]
# 3. Specify the collection 
col = db["student"]

# 1. Add the document 
# col.insert_one({"name": "lee", "age": 18, "sex": "M"})
# col.insert_many([
#     {"name": "tomas", "age": 15, "sex": "M"},
#     {"name": "misa", "age": 18, "sex": "F"},
#     {"name": "meng", "age": 15, "sex": "F"},
#     {"name": "meixi", "age": 16, "sex": "M"},
#     {"name": "que", "age": 20, "sex": "M"},
# ])
# 2. Search for documents 
# res = col.find_one()
# print(res)
# res = col.find()
# print(res)  # <pymongo.cursor.Cursor object at 0x7f1213e26668>
# for i in res:
    # print(i)

# 3. Modify the document 
# col.update_one({"name": "misa"}, {"$set": {"age": 15}})
# col.update_many({"age": 15}, {"$set": {"age": 88}})

# 4. Delete the document 
# col.delete_one({"name": "misa"})
# col.delete_many({"age": 88})
col.delete_many({"$or": [{'name': 'lee'}, {'name': 'meixi'}, {'name': 'que'}]})

res = col.find()
for i in res:
    print(i)